This invention relates to postal systems for determining the proper postage for items to be mailed. More particularly it relates to an interface between a weighing cell for determining the weight of such items and a data processing system for determining the appropriate postage in accordance with such weight and other postal information.
Postal systems for automatically determining the appropriate postage for items to be mailed are well known in the art and have contributed greatly to increased efficiency in mail handling procedures. One such system is described in U.S. Pat. No. 4,395,756 to Edward P. Daniels, July 26, 1983. The system disclosed in this patent comprises a microprocessor based system processor with a keyboard and display, a scale subsystem processor, forming part of a weighing cell, for providing weight information in digital form to the systems processor and a plurality of peripheral postal devices interfaced to the system processor. Another such system is disclosed in copending, commonly assigned patent application Ser. No. 430,091, now, U.S. Pat. No. 4,603,400, by Edward P. Daniels, filed Sept. 30, 1982, which describes a postal system comprising a microprocessor based system processor with keyboard and display, a scale weighing device operatively connected to the system processor and, postage printing subsystem and peripheral subsystem processors connected to the system processor through a serial communications interface.
Each of the above systems share the common feature of being an integrated system where all major system and interface are provided by one system vendor and are designed by that vendor to be compatible. However, with the increased computational load that is required from current generation mailing systems it is desirable to be able to interface mailing system peripherals to microcomputer systems provided by vendors who do not normally participate in the mailing system market. This capability is particularly desirable to allow a digital systems vendor to join with a traditional mailing systems vendor in seeking some of the very large contracts being awarded by the U.S. Postal Service, as well as foreign post offices, as they begin to automate their operations.
One particularly desirable interface would provide for the interconnection of mailing systems peripherals to data processing systems having ports of the type known as Optically Coupled Interface Adaptor and described in the attached Appendix. Such ports have separate serial input and output lines, each having an associated clock line. The port outputs data by strobing out a serial data word on a Send DATA (SDATA) line with a burst of clock pulses on the associated clock line. Data may be sent at an arbitrary time. Data is input to the port by strobing in a serial data word on a Receive DATA (RDATA) line with a burst of clock pulses on the other associated line, when the Receive Data line is driven to an asserted state. (Ports of this type will hereinafter be referred to a OCIA type ports.)
Thus, it is an object of this invention to provide an interface between mailing system peripherals and OCIA type ports.
It is a further object of this invention to provide an interface between a weighing cell and an OCIA type port.
It is still a further object to provide an interface where weight information may be received from the weighing cell as a series of coded digits representing the weight of an item to be mailed in arbitrary weight units and wherein the weight information is accompanied by status information from the weighing cell.